1. Field of the Invention and Related Art Statement:
The present invention relates to a small-size electronic viewfinder adapted to a handy camera for broadcast use, an industrial television (ITV) camera, a camera for home video use and the like as well as to a high definition television camera, particularly, to a viewfinder of this kind, the focusing of which onto a target can be remarkably easily adjusted in comparison with the conventional one.
It is fairly difficult to instantaneously and skillfully adjust the focusing of the conventional viewfinder provided with a small-sized (CRT) of, for instance, 1.5 to 2 inch with one eye. Particularly, it is still more in the situation of the ordinary moving scenery. Meanwhile, in the situation of the high quality television featured by the high definition and the large screen, a gross deterioration of definition is caused even by a slight misadjustment of the focusing of the camera, which is enlarged in the viewing screen.
Consequently, it is regarded by the group of cameramen that the adjustment of the camera focusing is a significant difficulty on the application of the camera. It is because the absolute area of the viewing screen of the small-sized CRT provided in the viewfinder is too small to accurately find the viewed target thereon, as well as the muscles driven for controlling the function of eyeball regulation is apt to be imposed with the burden based on the alternate operation thereof between the natural viewing and the close gazing on the viewfinder with one eye at close range. This is still more for persons of old year and of farsightedness.
On the other hand, in the conventional viewfinder provided with the small-sized CRT, the picture viewed thereon is not necessarily clear because of the coarse pitch of the shadowmask thereof and the limited bandwidth of the composite color television signal displayed thereon, and further the dot interference caused by the 3.58 MHz color subcarrier is added to the above, so that the adjustment of the focusing is extremely difficult.
As a result, although a colored viewfinder has been strongly demanded for a long time, it has been scarcely realized except for a few special kinds of television cameras.